The present disclosure relates to an energy measurement system, device and method, and more particularly to an energy measurement system to measure the energy level of laser radiation, including radiation level of short-pulsed laser beams.
Generally, systems to measure the energy levels of laser radiation are implemented using integrator circuits (e.g., with operational amplifiers), a gain amplifier and low-pass filter. In such implementation, the integrator circuit is used to average the signal energy from a photo-detector device, such as a diode amplifier. An integrator circuit typically tracks input signals with a delay that is based on the capacitance of the integrator circuit, and thus such a circuit has a tracking delay of 1/sC. Consequently, Energy measurement systems implemented using integrator circuits experience difficulties responding and tracking signals having fast rise times and low repetition rates. For example, a short pulse laser beam requires the integrator to respond quickly and then hold the resultant signal long enough to be sampled by an analog to digital converter. A measurement system that uses an integrator device also requires the entire signal chain, including the A\D converter coupled to the integrator, to have the bandwidth and rise time necessary for fast signal acquisition so that the incoming signal is acquired and converted before a significant change in that signal's level occurs.